Method of making lead acid storage battery



'Feb. 10, 1970 SHQELD 3,494,800

METHOD OF MAKING LEAD ACID STORAGE BATTERY Filed April 8, 1968 2 Sheets-Sheet 1 FIGI PAPER iNVENTOR LEAD FOIL

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Feb. 10, 1970 M. SHOELD 9 METHOD OF MAKING LEAD ACID STORAGE BATTERY Filed April 8, 1968 2 Sheets-Sheet 2 H04 MEN OR monms United States Patent 3,494,800 METHOD OF MAKING LEAD A'CID STORAGE BATTERY Mark Shoeld, 2140 E. Graves Ave., Orange City, Fla. 32763 Filed Apr. 8, 1968, Ser. No. 719,348 The portion of the term of the patent subsequent to July 30, 1985, has been disclaimed Int. Cl. H01m 35/18 US. Cl. 136-176 Claims ABSTRACT OF THE DISCLOSURE A lead acid storage battery of the jelly-roll type is mass produced by rolling up a plurality of strips of paper-like porous insulating material with lead foils between them and electrode material between the lead foils and the paper-like strips. One foil is part of the positive electrode and extends edgewise beyond the paper-like strips in one direction, while the other foil is part of the negative electrode and extends edgewise beyond the paper-like strips in the other direction. Lead wool electrical-1 interconnects the edges of each foil at each end of the roll, with lead terminal plates on the outer sides of the wool and plastic plates on the outer sides of the terminal plates, the assembly being held together axially by plastic bolts and nuts.

The present invention relates to storage batteries having spiral electrodes of the loose-paste type, more particularly of the lead-acid type such as described and illustrated in my copending application Ser. No. 637,219, now Patent No. 3,395,043, filed May 9, 1967, and to methods for their mass production. Preferred embodiments are illustrated in the accompanying drawings, in which:

FIGURE 1 is a diagrammatic view of the apparatus for assembling the elements of a storage battery according to the present invention, illustrating schematically the present method;

FIGURE 2 is an enlarged fragmentary top plan view of a strip of paper-like material receiving fluent electrode material;

FIGURE 3 is a perspective view of the expansible mandrel with components of the battery thereon in the position they occupy at the beginning of the formation of a battery electrode unit according to the invention; and

FIGURE 4 is a cross-sectional view of a completed battery according to the invention.

Referring now to the drawings in greater detail, there is shown apparatus for mass producing lead-acid storage batteries according to the present invention comprising a rotatable expansible spindle 1 of conventional construction, adapted to receive and releasably grasp t hereon an elongated cardboard, plastic or other type of tube 3 which provides a core or mandrel for the formation of the battery. Tube 3 may, for example, have a length of twelve inches and an outer diameter of about an inch and be of the conventional rigid pasteboa-rd type. When placed on spindle 1 as in FIG. 3 and the spindle expanded, the tube 3 is rotatable with the spindle; but when the segments of spindle 1 are collapsed, then tube 3 with or without a formed battery thereon can easily he slid on or ofI of spindle 1.

A plurality of webs of paper or paper-like porous insulating material 5, 6, 9, 11, 13 and 15, of the type described in my above-identified copending application, such as high wet strength Kraft paper, are wound up on tube 3, with lead foils 17 and 19 between them. The paperlike webs and the lead foils are supplied from relatively large rolls of the same, which are power driven to un wind. As in my above-identified copending application, lead foil 17 is a positive plate-forming foil and projects edgewise outwardly beyond its associated paper-like webs or strips a short distance in one axial direction; while lead foil 19 is the negative-forming electrode and projects edgewise outwardly beyond its associated paper-like webs a short distance in the opposite axial direction.

Feed rolls 21 are provided for regulating the speed and position of the webs of paper-like material and the lead foils. Each web or lead foil is provided with at least one such set of feed rolls. The showing of FIG. 1 is entirely diagrammatic, however, and does not purport to represent the actual path of the webs and the foils nor the actual number of feed and idler rolls. Suffice it to say that rolls 21 are driven at constant angular velocity and are all of the same size, so that the feed of the paperlike Webs and the lead foils is at constant linear velocity for all of them. But as the diameter of the rolls from which the paper and lead are fed decreases during feeding, and as the diameter of the sandwich that is building on mandrel 3 increases, it is obvious that the supply rolls and the spindle 1 must be driven at angular velocities that continuously vary. To this end, any of the conventional means for winding superposed webs at uniform velocity may be employed, such as a constant torque drive for spindle 1 that drives mandrel 3 at variable angular velocity dependent only on the tension in the webs and foils, and a variable velocity drive for the supply rolls that is controlled by a photoelectrically sensed position of a suspended bight of paper-like web or lead foil between the supply roll and the feed rolls 21.

The lead foil 17 is pressed against its underlying paperlike web 5 by means of a pair of pinch rolls 23; while the lead foil 19 is pressed against its underlying paper-like web 15 by a pair of pinch rolls 25.

Upstream of pinch rolls 23, with regard to the direction of web travel, a pair of applicator pipes 27 disposed above web 5 as shown in FIG. 2 applies a paste of lead peroxide containing 30% by weight of water, balance lead peroxide, to the upper surface of web 5. This lead peroxide paste is then rolled out between web 5 and foil 17 by pinch rolls 23 to a depth of about 0.006". On top of foil 17, downstream of pinch rolls 23, another set of applicator pipes 27 adds the same quantity of the same lead peroxide paste to the upper surface of lead foil 17, which is then rolled out to the same depth between foil 17 and paper web 7 upon passage about mandrel 3.

As shown at the right of FIG. 1, colloidal lead paste of conventional composition and about 30% by weight water content is applied upstream of pinch rolls 25 by a pair of applicator pipes 29 to the lower paper-like web 15, which is then pressed out between pinch rolls 25 to the same depth as before; while downstream of pinch rolls 25, a further pair of applicator pipes 29 applies further colloidal lead paste to the upper surface of lead foil 19, the paper-like web 13 being then pressed down upon passage about mandrel 3.

A paper-like web 9 of porous insulating material thus is disposed between the webs 7 and 13 in the completed rolls; while a similar web 11 is disposed between the webs 5 and 15. As in the copending application, these webs may have, for example, a thickness of 0.008" and a porosity of approximately 60% and weigh ounce per square foot dry, and be acidproof and of high wet strength by virtue of the inclusion of rubber latex in their manufacture. The lead foils, as in the copending application,

3 may, for example, be 0.002" thick. Webs 9 and 11 serve as separators between the composite positive and negative electrode assemblies.

As best seen in FIG. 2, the paper webs have thickened or raised edges 31, which as explained in the copending application serve as edgewise outward retainers for the colloidal lead and lead peroxide pastes. These raised edges 31 may be formed in any desired manner, for example, integrally with the material of the web during manufacture, or as applied strips held on by pressuresensitive or other adhesive, or by folding over an edge of the web. They are preferably about /2 wide or less.

Care is taken that the paper Webs and lead foils do not become laterally misaligned during winding. To this end, any of the conventional means for maintaining the proper lateral position of a strip or web may be used.

For example, edge feelers can be used, or Askania roll units (not shown) of conventional construction can be employed in connection with or independently of the drive rolls 21.

In starting the windup operation, the tube 3 is slipped on spindle 1, which is then expanded to grip the tube. The ends of the webs 5 and 15 are then fastened to tube 3 with adhesive tape 33 as best seen in FIG. 3. The ends of the webs 7, 9, 11 and 13 are also similarly attached, either to the tube 3 or to the webs 5 and 15. The machine is then started for a run of a short predetermined distance, approximately two or three wraps and is then stopped. The lead foils 17 and 19 are then adhesively taped onto the webs 5 and 15, respectively, and the machine is then started again, as well as the measuring pumps (not shown) by which the pastes are suppied to the applicator pipes 27 and 29. After predetermined lengths of paper web and lead foil with the pastes have been fed off and wound on the tube 3, the machine is stopped and the lead foils are cut off. The machine is then restarted with the paper-like webs only, for about two wraps. The webs are then cut olf close to the roll and taped to the roll. After this, a thin polyethylene sheet of about .001" thickness or less is wrapped around the roll and fastened with small pieces of adhesive tape to improve the scuff resistance during handling.

Expansible spindle 1 is collapsed and the completed roll is slipped 01f the mandrel. A plastic bolt 35 is then positioned centrally within the tube 3, and is centered therein by means of annular plastic spacers 37, as best seen in FIG. 4. Discs of lead wool 29 are then placed against each end of the roll, so that a portion of the lead wool contacts each turn of each foil. Of course, one foil will thus be in electrical connection with one disc of lead wool but not with the other; while the other foil will be in electrical connection with the other disc of lead wool but not with the first-mentioned disc. Perforated lead plates 41 are then slipped over the ends of plastic bolt 35 and pressed against lead wool 39. One of the plates 41 in electrical contact through the lead wool with the positive electrode has a lug 43 providing a positive terminal while the other lead plate 41 in electrical contact with the negative electrode has a lug 45 providing the negative terminal. Perforated plastic plates 47 are then slipped over the ends of bolt 35 and lugs 43 and 45, and plastic nuts 49 are applied on the opposite screw-threaded ends of bolt 35.

Plastic bolts 51 parallel to plastic bolts 35 also surround the roll and pass through cars 53 formed integrally on plastic plates 47. Nuts 55 are tightened on bolts 51 against ears 53.

To add the electrolyte, a plurality of the rolls are disposed with their axes horizontal in a lead-lined vacuum tank. A nearly complete vacuum is then produced, and sulfonic acid of 5 3 Baum is introduced. The pore spaces of the Kraft paper or other material are thus filled; and with the water in the paste, an acid electrolyte of 1.28 specific gravity is achieved, which is desirable for the fully charged battery. On discharge, the acid strength goes down to about 1.20 specific gravity. The vacuum is released when the rolls are. fully covered with acid. The acid is then drained from the tank and the units removed and tested.

If upon testing the rolls are found to be defective in any way, then the plastic components are removed and the roll is reclaimed as described in my copending application Ser. No. 654,739, now Patent No. 3,395,010, filed July 20, 1967. But if the units are satisfactory, then they can be incorporated in a plastic casing with a plastic top, as in my copending application Ser. No. 637,219, now Patent No. 3,395,043. The plastic parts can be reused indefinitely; and by use of an economical recovery system as indicated above, the cost of the battery over its useful life is very small.

Although the present invention has been described and illustrated in connection with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit of the invention, as those skilled in this art will readily understand. Such modifications and variations are considered to be within the purview and scope of the present invention as defined by the appended claims.

Having described my invention, I claim:

1. A method of making a lead-acid storage battery comprising forming an electrode assembly by continuously and simultaneously feeding separate and indefinite lengths of a positive electrode of lead foil, paper layers of porous insulating material, and a negative electrode of lead foil, said lengths of material being arranged so that foils are interposed between said paper layers of porous insulating material, feeding and depositing paste of colloidal negative electrode material in contact with the surface of the negative electrode foil and a paste of colloidal positive electrode material in contact with the surface of the positive electrode of lead foil, spirally winding ona mandrel said lengths of material, at least said foils being associated during Winding on said mandrel.

2. A method according to claim 1 in which further layers of paper porous insulating material are wound on the mandrel between adjacent layers of the paper insulating material on opposite surfaces of the lead foil.

3. A method according to claim 1 in which the mandrel is detachably attached to a rotating mechanism to rotate said mandrel about its axis, layers of the paper insulating material are attached to the mandrel and several convolutions wound thereon, before attaching the foil thereto and after a predetermined quantity of foil, insulating material and paste are wound on the mandrel, the feed of paste and foil are terminated, and several turns of insulating material are wound about the assembly.

4. A method according to claim 3 in which the speed of rotation of the mandrel and the feed of the foils and insulating layers are correlated to maintain the linear speed of feed constant.

5. A method according to claim 1 in which the layers of paper insulating material between which and the metal foils the paste is deposited are provided at the longitudinal edges thereof with retaining portions to prevent the paste from discharging from the assembly.

6. A method according to claim 1 in which the lead foils are fed from sources of supply to the mandrel in a generally horizontal direction and the stretches of lead foil between the sources of supply an the mandrel are supported on generally horizontal stretches of paper insulating material.

7. A method according to claim 6 in which the pastes of colloidal electrode material are fed onto the generally horizontal stretches of paper material and onto the lead foils after the foils are supported by the paper material.

8. A method according to claim 6 in whichthe pastes of colloidal electrode material are fed onto the generally horizontal stretches of paper material before the lead foils are contacted with the' paper-like material to support the foils, and the paper material and foils with the colloidal electrode material therebetween are passed through spaced rollers.

9. A method according to claim 8 in which additional layers of colloidal electrode material are deposited on the lead foils after the lead foils are in contact with their supporting paper materials and the last so deposited colloidal electrode material is pressed between the foils and strips of paper insulating material.

10. A method according to claim 9 in which the layers of paper insulating material between which and the metal foils the paste is deposited are provided at the longitudinal edges thereof with retaining portions to prevent the paste from discharging from the assembly.

References Cited UNITED STATES PATENTS WINSTON A. DOUGLAS, Primary Examiner 0 A. SKAPARS, Assistant Examiner U.S. Cl. X.R. 

